1. Field of the Invention
This invention relates to means for drying freshly washed vehicles, and more particularly, to a pivotally mounted self-stabilized overhead drying apparatus having a nozzle to direct a high velocity airstream on a vehicle moving therebelow.
2. Description of Related Prior Art
It may be useful to review related prior art disclosures to ascertain the pertinent techniques for drying freshly washed vehicles. Anderson U.S. Pat. No. 2,949,678 discloses an elevated vehicle dryer having a nozzle with a self-positioning mount. The blower motor is rigidly attached to the upper portion of a stationary support structure which is situated laterally of a vehicle conveyor. The air flow from the blower is delivered by a feed duct to a right angle member which is connected through flexible duct material to an elongated duct centrally positioned over the vehicle conveyor track and terminated in a nozzle. The elongated ductwork in cooperation with the flexible duct material is pivotally mounted on an overhead structure to move about a lateral axis to maintain clearance with respect to the profile of a vehicle advancing therebelow. A counterweight mounted on the end of a boom, which is attached to and extends longitudinally of the elongated duct across the pivot axis in a direction opposite the nozzle, produces a static force to balance substantially the weight of the ductwork extending from the pivot axis to the nozzle. Balancing the rotational forces generated by the discharge of air from the blower and through the nozzle is accomplished by vertically offsetting the pivot axis relative to the aperture at the end of the elongated duct opposite the nozzle.
To dry a vehicle successfully, the Anderson invention requires a dead weight suspended over the path of a vehicle approaching the drying nozzle. Apart from the potential damage to the vehicle should the weight be dislodged and fall, the presence of a substantial weight positioned at the end of a pivotally mounted boom presents a constant danger of injury to anyone working in its vicinity.
The Anderson invention also suffers from operational disadvantages stemming from the need for extensive, elaborate ductwork to deliver a high velocity airstream from a blower situated at a substantial distance from the discharge nozzle. Lengthy ductwork having abrupt contours away from the blower aperture necessitates the use of a higher energy motor to sustain a high velocity airstream. Discharging higher velocity air, however, necessitates the use of a feed duct increased in size to eliminate back pressure, which further diminishes the velocity of air available at the orifice of the discharge nozzle.
In addition, Anderson discloses no structural means to fix the nozzle orifice to discharge air in a constant direction upon pivotal movement of the elongated duct during a drying operation.
Capra U.S. Pat. No. 3,742,615 discloses a pair of blowers pivotally mounted on an inverted U-shaped structure that moves relative to the length of the vehicle. Motion of each blower about its pivot axis is controlled by either a pneumatic or hydraulic jack which is mounted on the structure. Capra uses the jack not only to sweep the nozzle across the surface of the vehicle, but also to furnish a constant external force to stabilize the blower assembly while it remains stationary. The Capra invention, therefore, does not teach the present invention because it employs an external mechanism, which does not function as a counterweight, to stabilize a pivotally mounted blower apparatus.
Additional prior art can be classified into two general categories, neither of which teaches the present invention. The first category includes Vani U.S. Pat. No. 3,367,040, Rupp U.S. Pat. No. 3,805,410, and Peters U.S. Pat. No. 3,808,698. Each of these features an apparatus which houses an air blower assembly that remains stationary throughout the drying operation. The drying operation is accomplished by advancing the vehicle through a structure which houses extensive ductwork that directs forced air to nozzles spaced about the surface of the vehicle. Peters does show a relatively short rotatable overhead nozzle; however, the heater assembly and primary ductwork remain fixed. Because each blower assembly is rigidly secured to its support structure, none of these apparatus requires the use of a counterweight assembly of any type.
The second category includes Heinicke U.S. Pat. No. 3,375,592, Von Kulmer U.S. Pat. No. 3,780,448, and Burger U.S. Pat. No. 3,787,986. Each of these discloses an air blower apparatus securely mounted on an inverted U-shaped structure that directs forced air over the surface of the vehicle by either guiding a nozzle attached to flexible ductwork that is in contact with the vehicle as it passes through or moving the entire structure along the length of the vehicle. In contrast to the present invention which pivotally mounts the air blower assembly about an axis and utilizes an integrated internal mechanism for stability, the apparatus of this second category achieve inherent stability by keeping the air blower fixed.
Burger U.S. Pat. No. 3,787,986 shows an alternative embodiment for a small pivotally mounted blower apparatus adapted for manual handling and control. This embodiment, however, neither possesses external ductwork, which would necessitate counterbalancing, nor utilizes any internal stabilization means to balance the apparatus, a function which is incumbent in part upon the operator to accomplish.
None of the references discussed hereinabove discloses a pivotally mounted overhead drying apparatus having an internally stabilized structure to self-position the apparatus and to promote efficient drying of a freshly washed vehicle advancing therebelow. A primary object of this invention is, therefore, to accomplish this task by providing a pivotally mounted overhead drying apparatus featuring an integrated structure including a blower, ductwork and discharge nozzle which can be slidably positioned to balance substantially torque generating forces on both sides of the pivot axis without necessitating the use of an external counterweight. The drying apparatus is capable of maintaining the disposition of the nozzle orifice to discharge air in a fixed direction over the vehicle as the apparatus pivotally moves in response to the profile of the upper surface of the vehicle moving thereunder.
A further important object of this invention is to provide an overhead drying apparatus that is capable of discharging a substantial volume of air through the use of relatively short ductwork, thereby allowing the use of a low power blower.
Another important object of this invention is to provide an overhead drying apparatus capable of delivering through ductwork of relatively small cross section to a discharge nozzle a large volume of forced air having uniform flow characteristics.
Still another important object of this invention is to provide an overhead drying apparatus which is capable of using a low power blower to generate a sufficiently large concentrated airstream and which apparatus facilitates greater versatility in specifying the elevation with respect to the vehicle and directional capability of a discharge nozzle.
The overall advantage of the present invention is the capability for accomplishing safe and efficient drying of a freshly washed vehicle by means of an overhead drying apparatus comprising compact ductwork coupled to a blower having a reduced power rating.